[Animal Modeling]-Clinical Evaluation of Nutritional Diet in the Treatment of Canine Keratoconjunctivitis Sicca

  Background: Dry keratoconjunctivitis, also defined as "dry eye syndrome", is a disorder of the tear film that causes damage to the surface of the eyelid. Canine keratoconjunctivitis (CKCS) is an inflammatory eye disease that not only affects the cornea and conjunctiva, but is also related to the lack of tear water content. The current treatment of ocular diseases relies on immunosuppressive therapy, represented by cyclosporin A, glucocorticoids, tacrolimus and artificial tears to restore adequate eye lubrication. However, the accepted complementary or alternative treatments are cholinergic (pirocarpine) and surgical treatment (punctal obstruction, meibomian suture, conjunctival flap, contact lens, superficial keratectomy, parotid duct transfer )to represent. The clinical response to treatment is often different, depending on the clinicopathological state of the eye at the time of diagnosis and the individual's response to treatment. Among other causes of CKCS trauma, congenital causes, canine distemper, radiotherapy, neurological deficits, diabetes, and uncorrected protruding gland prolapse are worth noting. Most of these aspects can be related and contribute to the determination and deterioration of the inflammatory state of the eye tissue. It may be useful to use therapeutic adjuvants in the management of CKCS to improve response to drug therapy. A comprehensive treatment approach based on the administration of classic drugs and the use of an anti-inflammatory/antioxidant diet with potential immunomodulatory activity was evaluated. The use of commercially available nutritious food as a therapeutic adjuvant for the treatment of CKCS-affected dogs was evaluated, which is not sensitive to standard pharmacological responses. Melon has certain antioxidant and anti-inflammatory effects, involving the removal of superoxide/peroxynitroso anions and the production of macrophage interleukin-10, and the immunomodulatory activity is through the induction of type 1 helper T lymphocytes ( Th1) Polarized and played. The activity of nodule algae is related to the presence of sulfated polysaccharides, which can induce the secretion of nitric oxide, tumor necrosis factor (TNF) alpha and granulocyte colony stimulating factor (GM-CSF) in macrophages. Carotenoids induce lymphoblastogenesis and lymphocytotoxicity in mice, proliferation of T cells and B lymphocytes, and human natural killer cytotoxicity. After aloe extract is cultured in vitro for corneal cells, the production of interleukin (IL)-1β, IL-6, TNF-α and IL-10 can be observed.

  Experimental design, dog and diet: diagnosis of immune-mediated KCS: blepharospasm, conjunctival inflammation, corneal keratosis, corneal pigmentation density, neovascularization, mucus discharge, STT value<10 mm/min. Exclusion criteria: there are related systemic diseases, neurological diseases, trauma and toxic keratoconjunctivitis, in order to better evaluate the immune-mediated clinical response of CKCS or general symptoms of intolerance/allergies, test in the clinical evaluation Ingredients of nutritious food. In addition, subjects affected by neurological CKCS were excluded. Fifty dogs were randomly divided into two groups: 25 dogs were fed a standard diet (SD group) as a control group, and 25 dogs were fed an antioxidant/anti-inflammatory nutritional diet (ND group) as an experimental group. Male and female dogs are the same in both groups. Regardless of the type of diet, all dogs are treated as follows within 60 days: 0.03% tacrolimus, benzylammonium chloride and methylcellulose solution, 0.2% hyaluronic acid eye drops five times a day. The nutrient composition analysis of ND and SD food is similar (crude protein 24%, crude fat 12%, crude fiber 3.7%, crude ash content 5%, moisture 9%). Both diets have similar recipes, including the same macro and micro nutrients, including vitamins, trace elements and minerals. These two foods are mainly different from the presence of plant substances in ND foods. ND food consists of two mixed components: coarse ground, including an ideal 93-94% by weight, and cold compressed tablets accounting for 6-7% of the whole food. The tablets are composed of 60-80% hydrolyzed protein (fish and vegetables), 20%-40% of minerals are used as gliding agents and added with therapeutic substances (Chlamydomonas, Muskmelon, Papaya, Aloe, Haematococcus, Turmeric) , Camellia, pomegranate, pepper, echinacea, Grifola frondosa, soybeans, omega 3 and omega 6 unsaturated fatty acids from fish, 1.60% and 1.25% respectively). The daily diet is recommended for ND and SD diet management, and carefully adjusted during the experiment to provide similar calorie animal food intake and meet the nutritional needs of adult dogs. In order to avoid any deficiencies, the energy values of the two complete foods are calculated using the methods recommended in the Nutritional Requirements for Dogs and Cats and Nutritional Requirements for Dogs and Cats of the National and National Institutes.

  Eye examination: Each dog was evaluated by an independent observer on days 0, 15, 30 and 60. Ophthalmology examinations include slit lamp biomicroscopy, fundus microscopy, applanation intraocular pressure measurement, 0.4% oxygen brocaine hydrochloride applied to the eyes, and normal saline to reduce fluorescein staining. The eyes of each dog were taken during each observation in the afternoon (3-6 o'clock), and clinical symptoms (such as corneal pigment density and corneal keratosis) were graded according to the scores proposed by Hendrix et al. According to the score proposed by Moore et al., the conjunctival inflammation and mucus output were graded. Corneal pigment density (0-3): 0 = no pigment, 1 = the iris is easily visible through the pigment, 2 = part of the iris is revealed through the pigment, 3 = the iris is not visible through the pigment. Conjunctival inflammation (0-3): 0 = normal conjunctiva, 1 = mild hyperemia, 2 = moderate hyperemia with mild chemical anemia, 3 = moderate to severe hyperemia. Mucus discharge (0~3): 0=no visible mucus or transparent mucus; 1=scattered non-adhesive mucus; 2=moderate adhesive covering 25% of the cornea; 3=diffuse adhesive purulent secretion covering Corneal 25%-50%; corneal keratosis (0-2): 0±1, = mild opacity, 2 = moderate opacity.

  tear secretion test: put a standard test paper in the conjunctival sac of each dog to test for 60 seconds. Then the tear production was recorded at mm/min for each eye.

  Results: Clinical evaluation of eyes in ND and SD groups: Fifty dogs participated in the trial: 25 dogs received medication and standard diet (SD group), and 25 dogs received medication plus antioxidant/anti-inflammatory nutritional diet (ND group). The results of the study emphasized the clinical improvement in blepharospasm, eye congestion, peri-ocular swelling, and ocular discharge in the ND group, which largely depended on the use of nutritious food, because there was no significant improvement in the SD group. The comparative evaluation between the 0th day and the 60th day of the two representative dogs of the SD group did not show significant clinical improvement. Eyelid spasm, eye congestion, swelling around the eyes, and ocular discharge are still noticeable, or at least poorly improved. These results strongly pointed out the specific effects of the nutritional agent in inducing the anti-inflammatory and immunomodulatory effects of the ND group dogs. , Standard medical treatment is ineffective, because there is no significant improvement observed in dogs belonging to the SD group. In the course of drug treatment of CKCS, the effect of nutrients can be regarded as a high degree of clinical improvement.

  Improvement of canine CKCS score in ND group: The canine conjunctival inflammation score in the ND group decreased from baseline 2.1±0.1 to 0.6±0.1, while there was no significant change in the SD group (2.1±0.1~1.9±0.1). The corneal keratinization score in the ND group was significantly reduced (1.5±0.1~0.2±0.1), but there was no significant change in the SD group (1.5±0.1~1.4±0.1). The corneal pigment density and mucus output in the SD group were significantly reduced, while the ND group had no significant effect. The corneal pigment density score decreased from the baseline value of 0.9±0.1 to 0.2±0.1, while the mucus discharge score decreased from 1.8±0.1 to 0.3±0.1. The role of ND in improving the CKCS eye score test, and this phenomenon occurs independently of drug treatment, because the drug alone appears to be ineffective, such as the SD group. The STT-1 value improved only in dogs in the ND group 60 days after treatment, from the baseline value from 4.7±0.4 mm to 10.7±0.6 mm, but there was no significant improvement in the SD group. The results proved the effectiveness of ND in increasing the tear film. The anti-inflammatory effect of the nutrient solution helps restore the tear production of the physiological eye in CKCS.

  CKCS symptom recurrence/regression: After a 60-day evaluation, dogs in the ND group interrupted their diet for 30 days while continuing the medication. A rapid and intense recurrence of symptoms was observed 15 days after the interruption of ND. All dogs were re-supplemented with ND while continuing medical treatment for 30 days. Interestingly, the overall regression of symptoms was again observed after the reintroduction of ND. This result clearly shows the effect of nutritional therapy on dogs affected by CKCS, especially animals that are slow to respond to standard drug treatments.

  Conclusion: Using specific antioxidant/anti-inflammatory ND as the best combination of synergistic ingredients can combine with standard pharmacological therapies in CKCS to exert potential immunomodulatory activity. Nutritional treatments seem to significantly increase eye tear production, improve the clinical state of conjunctival inflammation, and improve corneal keratinization, corneal pigment density, and mucus output in CKCS dogs that are slow to immunosuppressive treatment.